Phone freezes, e.g. with Telegram

I got the phone back from repairs a few days ago. The result: According to their protocol they installed the newest FP OS on my phone and did nothing else, meaning:

  1. I can’t use WLAN, because that OS bug is still there. Does anyone else have that bug, too? Or am I the only one as well, as mentioned here?
  2. The freeze bug is still there, too. I used mobile data to install Telegram and test it.

This trashy non-support was given to me by the French Cordon Group. I am very close to just returning the phone, demanding my money back and never using this phone ever again. This forum here has been awesome, but now I need someone from the company who is actually capable of doing the super complex task of including the installation of Telegram into their test procedures so that they can actually verify whether or not the bug is gone. Is it possible to get in touch with such a human being in that company? Because if not, then the Fairphone is not for me.